In the development and maintenance of turf grass areas, such as golf greens or baseball and football fields, the composition of the underlying soil plays a significant part in the health and characteristics of the turf grass. In the original development of grass areas and in the subsequent monitoring of such areas for maintenance purposes, soil core samples are taken for analysis by experts to determine the proper nutrients to be used, watering amounts and intervals, as well as possible replacement or modification of particular areas, depending upon the characteristics of the soil core sample. It also is desirable, over the life of a golf green or a ball field, periodically to obtain samples from the same area of the field to determine how the soil composition changes over time to determine whether or not soil replacement or particular soil enhancement steps should be taken.
An early patent directed to the obtaining of soil core samples is the Melberg U.S. Pat. No. 1,109,446. This patent discloses a cutting tool which is pressed into the soil, and which includes an outer metal cutting core with an interior sample glass receiving tube in it. The core sample is pressed upwardly into the glass tube; and after the sample has been withdrawn, a cork or sealing device is placed in the upper open end of the glass tube. The entire unit then is inverted; and the glass tube is removed from the outer cutting tube. The other end of the glass tube then is closed; and the soil core sample may be stored and viewed at a subsequent time. It should be noted that there is nothing in the device or method of Melberg which stabilizes the position of the various components of the soil sample within the tube.
The Vollweiler U.S. Pat. No. 4,653,336 is directed to a combination soil auger and soil core sampler, which in many aspects is similar to that of the Melberg patent. In Vollweiler, the interior cylindrical soil-retaining insert is disclosed as being made of a variety of materials, including thermoplastic materials and stainless steel. Obviously, if materials which are not transparent are employed, it is necessary to remove the soil sample from the sample retaining insert in order to examine it. In all other respects, the disclosure of the Vollweiler patent is similar to that of Melberg.
The Bush U.S. Pat. No. 4,587,857 is directed to a method for mounting or stabilizing relatively unstable core samples from an oil drilling bore hole. The sample is obtained in a conventional manner by the drilling apparatus. The sample then is inserted into a length of heat shrinkable tubing. End plugs are inserted at each end of the sample; and the tubing is heated to cause it to shrink onto and to conform to the outer circumferential surface of the core sample. The tubing is cut off at the opposite ends of the core sample (which have had plugs inserted into them previously), and the entire assembly then is frozen prior to cutting off or squaring the ends and mounting the sample for subsequent viewing.
The Hensel U.S. Pat. No. 4,071,099 also is directed to a method for preserving a core sample from an oil well core. In the Hensel device, the core sample is encased, during the coring operation, into a rubber sleeve. Subsequently, the rubber sleeve is frozen. The sleeve then is placed in an elongated horizontal form and is cast around the greater portion of its circumference. An exposed portion of the rubber sleeve then may be cut away to expose the core for subsequent viewing and testing. The device and method of this patent is fairly complex; and it is not a simple hand operated method and apparatus.
The Clements U.S. Pat. No. 4,848,484 is directed to a hand operated soil extraction tool which has a pivoting door extending substantially along the length of it; so that a withdrawn sample can be directly viewed in the tool after the sample has been removed.
The Manchak U.S. Pat. No. 4,809,790 is an oil core device which freezes the core in place prior to its removal from the ground. Once again, this is a complex system and method for obtaining an intact core sample.
Two additional United States patents directed to oil drilling apparatus for obtaining samples from deep within the earth are Collee U.S. Pat. Nos. 5,360,047 and 5,560,438. These patents are based on the same disclosure, and disclose a technique for encasing a core sample as it is being obtained. This is done by inserting a gel material into the core sample; and the gel material is designed to solidify at temperatures slightly lower than those expected down-hole. As the core sample is withdrawn, the gel-like material solidifies to encapsulate the core to maintain its integrity during withdrawal and during subsequent transportation.
It is desirable to provide an apparatus and method for obtaining and preserving core samples which maintains the integrity of the sample in a simple and efficient manner, and which preserves the sample for subsequent visual observation over an indefinite period of time.